Transformer terminal connector



Jan. 8, 1952 R. a. SCHOONMAKER TRANSFORMER TERMINAL CONNECTOR Filed Feb.15, 1949 IINVENTOR. Eayifimd B Srammaiar DWMWLHW.

permanent Patented Jan. 8, 1952 TRANSFORMER TERMINAL CONNECTOR RaymondB. Schoonmaker, Poughkeepsie, N. Y.,

assignor to Fargo Mfg. Company, Inc., Poughkeepsie, N. Y., a corporationof New York Application February 15, 1949, Serial No. 76,519

3 Claims.

This invention relates to clamps in electrical connections and moreparticularly to connecting or clamping and supporting ends of cables orwires.

It is an object of this invention to provide an electrical connectorwhich will receive and grip the ends of cables and wires.

Another object of this invention is to provide and electrical connectorwhich will cooperate with, clamp, and connect the end of a cable or wireto a terminal.

A more specific object of this invention is to with, grips, supports andconnects cables and wires to a terminal in such a way that the wireswill be securely gripped and supported without strain or stress.

It is still another object of this invention to design a connector inwhich the gripping elements are applied to the cables or wires clampedand supported therein by tightening one part of said connector uponanother part of the same connector.

A further object is that of providing a unit which will embodyrelatively few parts, each of simple, rugged construction, such partsbeing capable of economical manufacture and assemblage by relativelyunskilled labor to furnish a unitary article operating over long periodsof time with freedom from all difficulties.

With these and other objects in mind, reference is had to the attachedsheet of drawings illustrating a practical embodiment of the in? ventionin which:

Fig. l is a sectional side view of a connector coupling the end of awire or cable to a terminal;

Fig. 2 a sectional side View of the connector of Fig. 1 minus the wireor cable and the terminal and showing the clamping element partly inelevation;

Fig. 3 is sectional end view taken along lines 3-4 and in the directionof the arrows as shown n Fig. l; and

{l is an exploded view of the terminal stud sleeve, gripping element andretaining ring of the connector shown in 1.

In genera tr e electrical connector of this invention connects a wire orcable to a terminal by a simple operation capable of being performedunder adverse conditions and clamps and supports the wire in such amanner as to provide a and secure electrical connection without stressor strain.

As shown in the figures, the connector of this invention has a clampingelement which grips ti lOllIlECt-Sd. wire or cable when the insulator to1, an inmlator if: has centrally disposed in its upper pGl'tlC-ll acylindrical recess terminating in bottom surface it. A funnel-shaped wedon to the terminal stud. Referring provide an electrical connector whichcooperates passage l3 extends upward from the lower rim.

14 of the insulator If! to a central aperture l5 in the bottom surfaceI2, thus providing a continuous passage from top to bottom through theinsulator H]. A terminal l6 positioned above the insulator H7 issuitably connected to an electrical line. An external thread I! on theend of terminal I6 receives an internal thread 18 in a bored stud H]which is. thereby fastened to the terminal l5. As shown in Fig. 4, asleeve 2| contains a, cylindrical chamber 22 which has threaded on itswall an internal thread 23. As shown in Figs. 1 and 2, thisinternalthread 23 receives an external thread 24 of the stud l9 so thatthe stud l9 may be screwed downward into the sleeve 2| which in turn iscentrally positioned in the recess H of the insulator so. The sleeve 2|seats with its lower end 25 on the bottom surface |2 of the recessCounterbored into the sleeve 2| from the lower end 25 are two recesses26 and 21. The upper recess 26 forms a shoulder 28 with the lower end ofthe chamber 22 and the lower recess forms a shoulder 29 with the recess26.

Referring to Fig. 4, clamping element 3| has.

. wardly to make up a frusto-conical surface 31.

and 2 fits into the sleeve 2| with the base 32 slipping into the recess26, the shaft sections 35 extending upward through the threaded chamber22 and the head sections 36 protruding out of the upper end. Thefrusto-conical surface 3'! is thus brought into contact with theinverted taper of the bore 38 as the sleeve 2| and stud H) are threadedtogether. A retaining ring 39 fits into the lower recess 21 at the lowerend of sleeve 2| and fitting snugly in the recess 21 seats against theshoulder 29 to hold the clamping element 3| in position within thesleeve 2|. It is noted, as shown in Figs. 1 and ,2, that the height ofbase 32 is not as greatas the depth of recess 26 which contains it, andtherefore while held securely in place by retaining ring 39 the clampingelement 3| is free to rotate on its axis within the sleeve 2|.

element 3| is inserted in the sleeve 2| and the ring 39 press-fittedinto the recess 27. The sleeve and clamping element assembly is thenpositioned in the recess ll with the lower end 25 of sleeve 2| seated onthe bottom surface l2 so that the center hole of ring 39 and the opencenter of element 3! form a passage M which *is aligned of the sleeve 2!as shown in Figs. 1, 2 and 3.

In this condition the insulator with the sleeve and clamping elementassembly secured therein is fastened on to the stud I9 which has beenpreviously screwed on to the terminal it as hereinbefore described. Thusthe frusto-conical surface 31 with its outward taper is brought intoengagement with the inverted taper of bore 38 as the threads ll and l8inter-engage. The head sections 36 are provided at the upper end oftheir inner surfaces with jaws d3 having teeth Q5. As the frusto-conicalsurface 3'! engages the tapered bore 38 the head sections 36 arepermitted to flex inward by the spring of the flexible shaft sections 35anchored in the rigid base 32. The jaws 43 are thus urged together intothe central passage 4! so as to constrict that passage in the area ofthe jaws 43. The further that the sleeve M is threaded on to the stud Isby rotation of the insulator It the greater will be this constriction.In Fig. l a wire 54 is shown inserted into the connector throughpassages l3 and M and clamped between the jaws 63 by the action betweensurface 3'! and tapered bore 38. The wire 64 is or may be suitablyconnected to the electrical line which it is desired to electricallyconnect to the terminal l6. The element 3! is preferably composed of amaterial having an elasticity suflicient to permit the fingers toreceive a range of wire sizes of at least from #10 stranded to #2 solidwithout permanent deformation. At the same time the material preferablyprovides teeth d5 with sufficient hardness to pierce the hard drawncopper of the ordinary conducting wire preferably over Rockwell B50. Ametal alloy composed of 91% copper, 2% silicon and 7% aluminum, having amodulus of elasticity in the neighborhood of 10 x l6 5 p. s. i. and ahardness of the order of Rockwell B85, is one example of such amaterial.

In the operation of this modification of the invention the stud l 9 isfastened on the threaded terminal to by means of external threads H andinternal threads E8, the terminal I6 being attached in some electricalcircuit which it is desired to complete by electrical connection withthe wire 44. The insulator l0 containing the sleeve 2| and the clampingelement 3! secured in position therein is then screwed on to the stud l9by engagement between threads 23 and 24. When sufiicient engagement to'hold the insulator in place on the stud H9 is obtained, the screwingoperation is interrupted while the end of wire 44 inserted throughpassages 13 and M is positioned between the jaws 43. The screwing of theinsulator and sleeve assembly on to the stud I9 is then resumed and bybringing the surfaces 31 and 38 in to further engagement causes the jaws43 to close in on the wire M and the teeth 45 to clinch the wire 44. Thejaws 53 thus coming into contact with the wire l i clamp and hold it inposition against removal. Thus the stud i9 is secured on the terminalIt, the sleeve 2! and the insulator ll] is secured on the stud l9 andthe wire 5 clamped in the jaws 43 is secured in, and supported by, theclamping element 31 and the electrical connector as a whole.

In the clamping operation the jaws 43 are closed on the wire 44 astightly as reasonably possible which is sufiicient for teeth 45 topierce surface layers of oxide or other matter on the wire 54.Consequently the insulator Ill and sleeve 2i are rotated with relationtothe stud it after the jaws have come into contact with the wire Q4 andhold it securely in position. The continued rotation of the sleeve 2!and the insulator I when the jaws' lS and wire 44 are in this conditionis not trans ated to the clamping element 3! and consequently nottransferred to the wire 54 because of the loose rotational fit permittedthe clamping element 3! by the freedom of base 32 in recess 26 and theabsence of contact between other parts of the element 3| and the sleeve2!! and the low coefiicient of friction. Thus in the last stages of thetightening of the insulator iii and sleeve 2| on the stud 19 when thejaws Q3 and wire id are in contact, these members, the clamping elementSt and wire as, remain stationary with the terminal It and the stud I9,while the insulator it! and sleeve 2| are rotated.

The wire 54, as shown in Fig. 1, extends downward and out from theelectrical connector, resting against the curved wall of thefunnel-shaped passage i 3. In Fig. 1 the wire 44 in lying against andfollowing the surface of the funnel passage I3 is introduced between thejaws 43 at a very small angle -to the axis of the head sections 36 andthe jaws 45!. As the wire M is held axially between the jaws 63 theintroduction of the wire M into the clamping position at a very smallangle to the clamping position provides that the fiexure of the wirebetween the support of passage l3 and the damping jaws 43 will be soslight as to be negligible.

Among other advantages of this invention the support of the connectedwire by the funnelshape of the insulator wall relieves strain placedupon the wire when it is seized by clamping. When a wire is deformedsome of its inherent strength is lost, when to this loss of strength isadded a severe flexure adjacent the weakened region, the probability ofcomplete or partial rupture of the wire is considerably increased. Thisinvention ameliorates the weakening of the wire by the clamping andobviates the possibility of rupture. As outlined above, this advantageis obtained by supporting the wire in the vicinity of the clamp-ing andby reducing the angle of possible flexure of the wire in the vicinity ofthe clamping area.

Another advantage of this invention is seen in not deforming theconnected wire by subjecting it to the rotation of the connected partsafter it has been seized in the clamping grip. This advantage isobtained by mounting the clamping element rotatably in the connectorparts so that as the connector parts are rotated in the tighteningoperation the wire may remain stationary and no torque placed thereon.

A further advantage is that of the range of sizes of wire that may beaccommodated in any single electrical connector of this invention. Forexample, the same electrical connector may clamp, secure, hold andconnect wires ranging in gauge from #10 stranded to .2 solid without anyloss of the benefits of this invention.

Further advantages of this invention are the simplicity of construction,the economical mantrfactors and assemblage possible in making such partsand the iewness of the number of parts necessary, Still furtheradvantages are found in the simplicity of attaching the connected line,the fool-proof nature of the connection and the reliability of itsoperation.

Still another advantage is found in the use of the teeth of the jaws toinsure a good contact between the connector and the conductor. As theclamping element is composed ofa material having hardness and elasticityto provide it with other desired advantages, such as flexibility of thefingers and hardness to reduce the friction in tightening the clamp, thesharpedged teeth are harder than the copper of the ordinary conductor.Then when the connector is tightened reasonably tight on the conductorthe teeth of the clamping element will dig into the conductor and insurea good electrical contact by piercing any insulating surface layer, andwill continue to maintain a good electrical contact because of theintimate bond between the two parent metals of conductor and connectorwill exclude further corrosion deposits.

Thus, among others, the several objects of the invention as specificallyaforenoted are achieved. Obviously numerous changes in construction andrearrangement of the parts may be resorted to without departing from thespirit of the invention as defined by the claims. For example, theinternally threaded passage 19 and the tapered bore 138 through stud 19may be divided into two parts by a solid transverse wall extendingacross the passage and forming an upper threaded portion for receivingthe thread i? of the terminal [6 and a lower tapered portion forreceiving the head section 36 of the clamping element 3!. The threadedportion and the tapered portion are thus made blind by the transversewall. It will thus be apparent that various modifications can be made inaccordance with the principle of the invention as disclosed herein andfor that reason it is not intended it should be limited other than bythe scope of the appended claims.

I claim:

1. A connector for securing an electrical conductor comprising incombination an insulator; a threaded sleeve supported in said insulator;a clamping element contained in said threaded sleeve comprisingelongated fingers, conductor securing jaws mounted on said elongatedfingers, and a central passage formed by said jaws and fingers extendingaxially through said clamping element for axially receiving anelectrical conductor; a threaded member engaging said threaded sleeve; asurface actuated by said threaded member engageable with said jaws froman axial direction opposite to the axial reception of an electricalconductor into said central passage, to move said jaws to a closedposition and a central bore in said insulator aligned with said axialcentral passage and terminating at the opposite end of said elongatedfingers from said jaws, said bore admitting an electrical conductor intosaid passage whereby said jaws secure in said clamping element at apoint removed from the entrance to said central bore, said electricalconductor being insertible in an axial direction counter to said jawsclosing motion of said surface.

2. An electrical connector for securing an electrical conductorcomprising in combination an insulator, a threaded cylindrical sleevecon tained in said insulator, a clamping element said jaws, an insulatorsupporting said cylindri cal sleeve, a threaded member engaging saidthreaded sleeve axially with relation to said central passage, a taperedbore in said threaded member engaging said frusto-conical surface onsaid jaws from one axial direction, and a central bore in said insulatorat the opposite end of said cylindrical sleeve from said threaded memberaligned with and tapering inwardly toward said central passage in theopposite axial direction from said tapered bore for admission of anelectrical conductor into said central passage from said opposite axialdirection whereby said jaws are securable on said insertible electricalconductor in said clamping element at a point removed from the entranceto said centralbore.

3. In a connector for an electrical conductor, the combination of athreaded stud to which the conductor is connectible, a threaded sleevethreading onto said stud with a rotary motion, a clamping elementcarried in said threaded sleeve and rotatably independent therefrom, anannular base supported in said threaded sleeve with a low coefficient offriction between the annular base and its supporting surface, flexibleelongated fingers extending axially through said threaded sleeve fromsaid annular base, movable conductor securing jaws mounted at the end ofsaid elongated fingers, an axially short conductor gripping innersurface on said jaws, a frusto-conical outer surface on said jaws, atapered bore in said threaded stud engaging said frusto-conical surfaceto flex said elongated fingers and move said conductor securing jawsinward, a surface contact between said tapered bore and saidfrusto-conical surface having a low coeii'icient of friction to permitrotation of said clamping element within said threaded sleeve and saidthreaded stud after said conducting gripping surface has been broughtinto engagement with said conductor by the action of said tapered boreon said frusto-conical surface.

RAYMOND B. SCHOONMAKER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 411,153 Lafierty Sept. 17, 18891,267,959 Becker May 28, 1918 1,649,923 Post Nov. 22, 1927 1,677,326Bowen July 17, 1928 1,942,661 Paulus Jan. 9. 1934 2,087,384 Lee July 20,1937 2,406,346 Buchanan Aug. 27, 1946 2,468,169 Carlson Apr. 26, 1949FOREIGN PATENTS Number Country Date 535,264 Germany Oct. 8, 1931 12,150England of 1915

